1. Field of Use
This disclosure is directed to an image-forming apparatus and an intermediate transfer member.
2. Background
Image-forming apparatuses in which a color or black and white image is formed by using an intermediate transfer member to electrostatically transfer toner are well known. When an image is formed on a sheet of paper in a color image-forming apparatus using such an intermediate transfer member, four color images in yellow, magenta, cyan and black, respectively, are generally first transferred sequentially from an image carrier such as a photoreceptor and superimposed on the intermediate transfer member (the primary transfer). This full color image is then transferred to a sheet of paper in a single step (the secondary transfer). In a black and white image-forming apparatus, a black image is transferred from the photoreceptor, superimposed on an intermediate transfer member, and then transferred to a sheet of paper.
Current intermediate transfer belts (ITBs) used in high speed machines are composed of multi-layer members that separate layer functions, for example, dual polyimide layer ITB (high-resistivity upper layer with low-resistivity lower layer), dual layer ITB (polyimide base layer and fluorine resin surface layer), and three layer ITB (polyimide base, elastic layer and fluorine resin top layer). The common design includes a polyimide base layer plus a functional surface layer, where the polyimide base layer provides mechanical integrity, while the surface layer provides certain functionality such as low surface energy.
The top fluorine resin surface layer in multi-layer ITBs is typically VITON (a fluoroelastomer), PFA or PTFE (fluoroplastics). Such surface layers are hydrophobic and somewhat oleophobic with a hexadecane contact angle of about 45°. More oleophobic surface layers are desirable for ITBs.